Mortgage Notes Payable

The Company had outstanding mortgage notes payable totaling approximately $4.3 billion and $4.4 billion as of December 31, 2014 and 2013, respectively, each collateralized by one or more buildings and related land included in real estate assets. The mortgage notes payable are generally due in monthly installments and mature at various dates through April 10, 2022.

Fixed rate mortgage notes payable totaled approximately $4.3 billion and $4.4 billion at December 31, 2014 and 2013, respectively, with contractual interest rates ranging from 4.75% to 7.69% per annum at December 31, 2014 and 2013 (with a weighted-average of 5.70% (excluding the mezzanine notes payable) at December 31, 2014 and 2013).

There were no variable rate mortgage loans at December 31, 2014 and 2013. As of December 31, 2014 and 2013, the LIBOR rate was 0.17%.

On July 1, 2014, the Company used available cash to repay the mortgage loan collateralized by its New Dominion Technology Park Building Two property located in Herndon, Virginia totaling $63.0 million. The mortgage loan bore interest at a fixed rate of 5.55% per annum and was scheduled to mature on October 1, 2014. There was no prepayment penalty.

Four mortgage loans totaling approximately $2.2 billion at December 31, 2014 and 2013 have been accounted for at their fair values on the dates the mortgage loans were assumed. The impact of recording the mortgage loans at fair value resulted in a decrease to interest expense of approximately $52.5 million, $34.4 million and $7.0 million for the years ended December 31, 2014, 2013 and 2012, respectively. The cumulative liability related to the fair value adjustments was $138.7 million and $191.2 million at December 31, 2014 and 2013, respectively, and is included in mortgage notes payable in the Consolidated Balance Sheets.

Contractual aggregate principal payments of mortgage notes payable at December 31, 2014 are as follows:




	Principal Payments
	(in thousands)
2015	$	26,184
2016	608,879
2017	2,821,750
2018	18,633
2019	19,670
Thereafter	675,657

Total aggregate principal payments	4,170,773
Unamortized balance of historical fair value adjustments	138,711

Total carrying value of mortgage notes payable	$	4,309,484